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Butterfly Leads Research Team to Peaks

If you were hiking above tree line on a July afternoon and a tiny, mostly brown butterfly flitted by your feet, would you notice?

It’s now been 36 years since a team from the Rocky Mountain Biological Laboratory did. And the flapping of that little butterfly’s wings sent ripples all the way to Washington – and beyond. The tiny creature joined the U.S. Fish and Wildlife Endangered Species list in 1991.

Tracking the rare, Uncompahgre fritillary, with a wingspan of about 1 inch and only a few days of its life spent flying about the tundra on the highest peaks in the San Juan Range, has now consumed the better part of 11 summers for Dr. Kevin Alexander, a professor of Biology at Western State Colorado University.

Each year, Alexander gathers a team of undergraduate students to scramble over rocks and scree to pitch their tents as high as 12,500 feet in the San Juans, southwest of Gunnison. They have learned much – including that the short-lived, weak flyers are more widely spread and numerous than first thought. Alexander says their lifecycle varies a bit, but it’s generally two years.

“The adults live only two to five days, and they’re nectar generalists, feeding on whatever is blooming,” he says. “But they only lay their ovopods on snow willows.”

These egg colonies live beneath the next winter’s snow and emerge the following summer as caterpillars that feed exclusively on the snow willows, tiny plants, seldom much higher than an inch, spread among grasses and other small plants of the alpine tundra. The caterpillars feed on the snow willows’ leaves and then go dormant to spend another winter beneath the snow. In their second summer, the caterpillars feed some more and then pupate, forming cocoon-like casings Alexander and his students typically find attached to rocks. With luck, they survive another winter beneath the snow before crawling from their pupae shells, flying, feeding on nectar, mating, laying eggs and dying – all in just a few days – the following summer.

“Their tiny behavior is distinct,” Alexander explains. “They’re weak fliers and stay close to the snow willows. They have unique markings under their wings – small shark’s tooth-shaped white patches.

“You might have a whole mountain up there and only two or three places they live. Sharing known habitat patches is how I train my crew. It’s one of those things that are very hard to put into words. But once I show them, they get it.”

Alexander’s annual crew of four to six students is a varied lot. They come from across the country and live for the summer in Lake City, about an hour from Gunnison. Many are biology majors. Some are studying environmental biology, or even geology. One recent student was pursuing an anthropology degree. Many return for additional summers, including several who worked for three years between college terms.

They not only watch for signs of the butterflies, their caterpillars and their pupae, but they also log sightings of other threatened and endangered wildlife, such as big horn sheep, mountain goats and ptarmigan. They have recommended routes for new trails, suggested other paths be removed to ease pressure on endangered species and helped maintain still other trails.

However, paths to find the butterflies are rare as the insects. Only two of 11 identified sites can be approached on foot-friendly tracks.

“There are no trails to these places,” Alexander explains. “There’s a lot of scree to traverse at high elevations. They’re hard to get to.”

The teams must hike 2 to 7 miles across untracked, unstable terrain to the sites. They often camp overnight, so they can work several days without repeating the hikes. They experience the entire alpine ecosystem, Alexander says, learning about “the environment, history, the whole thing.”

Alexander turns over data analysis for biological modeling to Dr. Andy Keck, chairman of the Western Mathematics & Computer Science department. Their funding comes from the U.S. Bureau of Land Management, U.S. Fish and Wildlife Service and the U.S. Forest Service, which all have roles managing the insects’ remote habitat.

The research team has learned the butterflies, while a unique and isolated species, seem to be holding their own. But the researchers have also learned the creatures’ schedules follow the weather, not strictly the calendar. That suggests climate change could hurt the butterflies, and Alexander suspects that is why they remain on the Endangered Species List.

“A sister species lives in the arctic tundra. This is an ice age relic. They’re very isolated. We've searched other mountain ranges around here and found nothing,” he explains, noting there is a similar butterfly found high in the Wind River Range of western Wyoming.

As he approaches another summer above tree line, Alexander expects at least two, experienced students to return from last year.

“It’s beautiful work,” he explains. “We’re above tree line every day. But it’s physically demanding. You’re climbing and carrying a backpack. Still, they love it. Just about everybody comes back for another summer.”